Rim widths..................

[FE600]

I am planning to use 185/60/13 and 205/60/13 on my PRB. Any sugestions as to the ideal rim widths for these (A032R's) tires? I was thinking of copying the R500 line of 6 1/2J and 8 1/2J rim size. Is this too wide, or this just the ideal for handling? Seems very wide to me. Some manufacturers have tables for the max width of the rims, while others say to use tread width (not section width) +/- 1/2" for the best handling. Any light shed on the subject, greatly appreciated.

PS PRB is an Australian Lotus 7 replica ~500KG only with monocoque construction using aluminium honeycomb. It has 4 times the torsional rigidity of the tube frame.

Regards Stuart

[Chelspeed]

Demon Thieves catalogue says 185/60 A032R's can fit 5.5 to 6 inch rims with 5.5 optimum. For 205/60 it's 6 to 6.5 with 6 optimum.

 

I've used both 185 and 205 on 6 inch rims without problems. For these size tyres I'd stick with 6 inch rims all round I think.

[Alex Wong1697456877]

I use 7" rims on my rear CR500's which I think are 205's. I used them at a Brands track day and they were fine. Prior to that, I used them on 6 inch rims on track days and to be honest, I can't say I've noticed a difference. They look better on the 7 inch rims but that obviously adds weight. I dare say that a better driver might notice the difference, but I didn't.

 

Alex

[Andy Checkley]

There maybe issues for you with regard to oversteer/understeer and the general balance of the car. The larger rears will give you better straight line grip, but assuming everything else is setup right will effectively increase understeer unless your engine has enough grunt to unstick them, and induce oversteer. Some people feel that you can't beat the balance of say a well setup 1600 K Supersport running with 13" 185's front and back. Having said that, from a cosmetic point of view, I think the larger rears fill the arches better and look the part.